Assessment of Damping Control Using Maximum Power Point Tracking Methods for Heaving Wave Energy Converters

Abstract

There are not many studies conducted in the implementation of maximum power point tracking (MPPT) methods for heaving wave energy converters (WECs). An assessment of damping control using various MPPT methods for heaving WEC was conducted in this study. Damping control was implemented using a DC–DC boost converter. The duty cycle for MPPT was determined using a perturb and observe algorithm. This assessment study determines the following for applying MPPT for heaving WECs: best location for the observing parameters; best performance index for the MPPT; and effect of averaging the performance index. Three locations for the observing parameters (mechanical parameters near the source, electrical parameters at the load, and electrical parameters between the source and load) and three performance indices (maximising power, minimising impedance, and maximising admittance) were assessed and evaluated. Finally, the effects of applying the running mean and conventional instantaneous value on the performance index were compared. Various scenarios using nine MPPT methods were tested using simulated regular and irregular sea states. The test results were validated experimentally using a simple and low-cost hardware-in-the-loop (HIL) scheme. The HIL scheme was developed using off-the-shelf devices that can be used for any topology of WECs. The results showed that the MPPT method has an optimum performance by using the performance index for maximising power, using observing parameters between the source and the load, and deploying conventional instantaneous values for the observing parameters.